"Only Texas has any sort of claim to a right to secede."
I would think California would also since it was an independant nation for, I believe, 3 days before we joined the US, the Republic of California.
It was never US teritory before joining the US.
It was two weeks, IIRC, and CA was never recognized as a nation by anyone else. It had no identifiable central goverment and had no defense forces of any kind. CA has NO claim, sorry.
Texas, on the other hand, had a standing Navy (which did very well against the Mexican Navy) that continues to this day as part of the USN. We had an army, of sorts; we were actually recognized as a nation by other countries, and we had foreign embassies. We had our own currency, a central government, and a Constitution. The state Capitol is taller than the US Capitol. Heck, even the UN says that we were/are a country, albeit annexed by the US.